Conventional nuclear medicine imaging systems include one or more gamma ray detectors supported by a gantry. The gantry typically provides mechanical movement of the detectors to allow the detectors to be positioned in various locations and orientations around the patient's body. Hence, image data can be acquired from various different angles about the patient. In conventional imaging systems, the gantry is a floor-mounted structure. In some systems, the gantry includes one or more closed, ring-shaped supports, to which the detectors are mounted. The detectors move in a circular path defined by the rings and are adjustable radially. The patient is placed within or next to the closed rings, and the rings are rotated with a motor to position the detectors appropriately about the patient.
Such systems have certain disadvantages. For example, because of their enclosed design, ring-based imaging systems and other enclosed systems tend to hinder studies of patients who are connected to intravenous lines and other life-supporting systems. For the same reason, such systems tend to be uncomfortable for claustrophobic patients. In particular, moving the patient through the rings may cause the patient anxiety. In addition, some such systems tend to be poorly suited for imaging wheelchair-bound patients and critically ill patients who cannot be moved from a hospital bed, or for imaging patients in either a sitting or standing position. These systems also tend to hinder the transfer of patients from a gurney to the imaging table, limit the attending technician's accessibility to the patient, and consume significant floor area.